The invention relates to molecules involved in cell death induction, methods and pharmaceutical compositions for cell death induction and uses thereof.
Antibodies have recently become the protein therapeutics of choice for targeting cancer but also for treating other indications (Brekke et al., Nat. Rev. Drug Discov. (2003) 2:52-62). The advent of antibody engineering has provided the tools to generate human antibodies from synthetic phage libraries, displaying decreased immunogenicity and enhanced specificity and affinity due to their human nature and greater diversity (Weiner et al., Nat. Biotechnol. (2005) 23:556-557). Naïve libraries are particularly attractive, as they may be used for isolation of antibodies for any specificity, including self-antigens (Griffiths et al., Embo. J. (1993) 12:725-734), independent of immunizations and reconstruction of new libraries. Cell surface receptors constitute by far the most successful group of antigens targeted by contemporary therapeutic drugs, including small molecule inhibitors and antibodies. Of particular interest are cell surface receptors that are uniquely expressed or that display an increased expression level on a target cell and are additionally capable of relaying death or survival signals to the cell. Such differentially expressed receptors with intrinsic signalling properties enable antibody-based targeting of microbial infected, transformed, or otherwise malfunctioning cells.
For treatment of tumours, antibodies that have the ability to induce cell death in a target tumour cell whilst sparing normal tissue are of particular interest. Several such antibodies are in use, have been registered with the US Food and Drug Administration (FDA) and provide alternatives to conventional cancer treatments e.g. for lymphoma (rituximab targeting CD20) or for breast cancer (trastuzumab or cetuximab targeting Her-2 and EGFR respectively).
There are also other antibodies with cell death inducing effects currently in clinical development. However, even if these antibodies demonstrate beneficial effects in patients or in animal tests an unmet clinical need still exists.
Anti-idiotypic immunoglobulin targeting of B cell tumours was the first monoclonal antibody therapy conducted in man (Miller et al. N. Engl. J. Med. (1982) 306:517-522). Destruction of tumour cells by such means of passive antibody administration (Riechmann et al., Nature (1988) 332:323-327), or active vaccination with the patient's own tumour immunoglobulin protein (Kwak et al. N. Engl. J. Med. (1992) 327:1209-1215), has since been demonstrated to confer tumour regression or tumour dormancy in patients with different kinds of B cell malignancies. A more recent report describes the generation of fully human anti-idiotype antibodies using transgenic mice deficient in mouse antibody production and expressing selected human antibody chain loci (Suarez et al. Mol. Immunol. (2004) 41:519-526).
In the present invention a competition biopanning method has been used, where target cell antigen in the form of whole cells, and excess subtractor cell antigen in the form of membrane vesicles, are exposed at the same time to the naïve n-CoDeR® antibody phage library (WO 2004/023140; Soderlind et al., Nat. Biotechnol. (2000) 18:852-856), to retrieve and subsequently test antibody fragments with excellent selectivity for B lymphoma target cells. Furthermore, functionality in the selected binding molecules was demonstrated by the ability of the antibodies tested to induce cell death in target but not in non-target cells.
Antibody specificities identified include ICAM-1 (the B11 antibody of the invention (also referred to as BI-505)) which is an adhesion molecule. Isolated antibodies had affinities in the sub-nanomolar to nanomolar range, directly making them possible choices for targeted antibody therapy.
ICAM 1 is highly expressed in several human malignancies and is believed to be involved in their pathogenesis (Aalinkeel et al., 2004; Hideshima et al., 2007; Huang et al., 1995; Johnson et al., 1988; Schmidmaier et al., 2006). Notably, ICAM-1 was recently reported to be over-expressed and associated with advanced disease and poor survival in multiple myeloma (MM) (Sampaio et al., 2009; Schmidmaier et al., 2006). Further, evidence suggests that ICAM-1 is upregulated and casually related to MM patient development of resistance to chemotherapy (Sampaio et al., 2009; Schmidmaier et al., 2006; Zheng et al., 2009). ICAM-1, by binding to integrin β2 receptors and muc 1, is involved in cell-adhesive events that trigger multiple cell-signaling pathways promoting MM cell proliferation, migration, resistance to apoptosis, and development of cell adhesion molecule-induced drug-resistance (Hideshima et al., 2007; Schmidmaier et al., 2004; Zheng et al., 2009). There is no curative treatment for MM and the currently available therapy is associated with significant toxicity and development of drug resistance (Kyle and Rajkumar, 2004). MM plasma cells typically do not express the B cell antigen CD20, or show low and heterogeneous CD20 expression, making CD20 targeted therapies ineffective in this disease (Kapoor et al., 2008; Richardson et al., 2011).
The inventors have now characterized MM plasma cells for expression of the ICAM-1 epitope targeted by their function-first isolated antibody BI-505, and demonstrate BI-505's therapeutic activity and mechanism-of-action in well-established experimental models of MM.